Semiconductor power module

ABSTRACT

A semiconductor power module including first and second power transistors situated in parallel between first collector and first emitter strip conductors. A first connection surface of each of the power transistors is electroconductively connected to the first collector strip conductor, and a second connection surface of each of the power transistors is electroconductively connected to the first emitter strip conductor, so that a current flowing between the first collector strip conductor and the first emitter strip conductor is divided between the power transistors when the power transistors are each conductively connected via an applied control voltage. A first external power contact is directly contacted with the first collector strip conductor at a first contact area, a second external power contact is contacted with the first emitter strip conductor at a second contact area via a first connecting element, and the second contact area is positioned asymmetrically between the power transistors.

The present invention relates to a semiconductor power module thatincludes a first power transistor and a second power transistor that aresituated in parallel between a first collector strip conductor and afirst emitter strip conductor. A first connection surface of the powertransistors is in each case electroconductively connected to the firstcollector strip conductor, and a second connection surface of the powertransistors is in each case electroconductively connected to the firstemitter strip conductor, so that a current flowing between the firstcollector strip conductor and the first emitter strip conductor isdivided between the two power transistors when the power transistors areeach conductively connected via an applied control voltage.

BACKGROUND INFORMATION

The power electronics for hybrid electric vehicles or electric vehiclestogether with associated semiconductor power modules are increasinglysubject to large installation space requirements, as the result of whichthe semiconductor power modules together with electrical supply lineshave smaller designs. At the same time, the current density increasesdue to increased power requirements. However, smaller supply lines andhigher currents result in greater electrical losses (ohmic as well asfrequency-related). Therefore, semiconductor power modules that areoptimized for installation space are generally mechanically built up inthe longitudinal direction, but this results in the electricalproperties being highly asymmetrical. For this reason, for a parallelconnection of power transistors, a first power transistor may take overthe switching-on operation and a second power transistor may take overthe switching-off operation. In particular when deactivating a shortcircuit, the short circuit capability may be greatly limited as aresult.

FIG. 2 shows by way of example a conventional semiconductor power module1′ the related art, designed as a so-called B2 bridge 1A′, that includesfour power transistors 5LA, 5LB, 5HA, 5HB designed as insulated gatebipolar transistors (IGBTs), and two free-wheeling diodes 3L, 3H. As isfurther apparent from FIG. 2, a first power transistor 5LA, a secondpower transistor 5LB, and a first free-wheeling diode 3L are situatedbetween a first collector strip conductor 11L and a first emitter stripconductor 9L, and form a low side of semiconductor power module 1′. Inaddition, a third power transistor 5HA, a fourth power transistor 5HB,and a second free-wheeling diode 3H are situated between a secondcollector strip conductor 11H and a second emitter strip conductor 9H,and form a high side of semiconductor power module 1′. The two collectorstrip conductors 11L, 11H are spaced apart from one another in the sameplane and are coupled to a cooling device, not illustrated. Therefore,the two collector strip conductors 11L, 11H each act as a heat sink fordissipating heat from semiconductor power module 1. The four powertransistors 5LA, 5LB, 5HA, 5HB and the two free-wheeling diodes 3L, 3Hare respectively situated on the two collector strip conductors 11L,11H, a first connection surface of power transistors 5LA, 5LB, 5HA, 5HBand of free-wheeling diodes 3L, 3H being respectivelyelectroconductively connected to a corresponding collector stripconductor 11L, 11H. A second connection surface of power transistors5LA, 5LB, 5HA, 5HB and of free-wheeling diodes 3L, 3H is respectivelyelectroconductively connected to a corresponding emitter strip conductor9L, 9H. In addition, the heat of power transistors 5LA, 5LB, 5HA, 5HBand of free-wheeling diodes 3L, 3H is dissipated via collector stripconductor 11L, 11H, respectively.

As is further shown FIG. 2, a first external power contact P at which analternating voltage potential is present is connected to the surface offirst collector strip conductor 11L at a first contact area KB1 andundergoes heat dissipation via same. A second external power contact TLat which a first direct voltage potential is present is connected tofirst emitter strip conductor 9L at a second contact area KB2 andundergoes heat dissipation via the first emitter strip conductor, viapower transistors 5LA, 5LB and free-wheeling diode 3L, and via firstcollector strip conductor 11L. A third external power contact TH atwhich a second direct voltage potential is present is connected to thesurface of second collector strip conductor 11H at a third contact areaKB3 and undergoes heat dissipation via same. Second emitter stripconductor 9H is electrically connected to first collector stripconductor 11L at a fourth contact area KB4 via a connecting element. Inaddition, illustrated semiconductor power module 1 includes even furtherexternal contacts KH, EH, G1H, G2H, KL, EL, G1L, G2L. External contactKL is connected to first collector strip conductor 11L or to collectorterminals of power transistors 5LA, 5LB of the low side of semiconductorpower module 1′ via a bonding wire. External contact EL is connected tofirst emitter strip conductor 9L or to emitter terminals of powertransistors 5LA, 5LB of the low side of semiconductor power module 1′via a bonding wire. External contact G1L is connected to a gate terminalof first power transistor 5LA of the low side of semiconductor powermodule 1′ via a bonding wire. External contact G2L is connected to agate terminal of second power transistor 5LB of the low side ofsemiconductor power module 1′ via a bonding wire. Analogously, externalcontact KH is connected to second collector strip conductor 11H or tocollector terminals of power transistors 5HA, 5HB of the high side ofsemiconductor power module 1′ via a bonding wire. External contact EH isconnected to second emitter strip conductor 9H or to emitter terminalsof power transistors 5HA, 5HB of the high side of semiconductor powermodule 1′ via a bonding wire. External contact G1H is connected to agate terminal of third power transistor 5HA of the high side ofsemiconductor power module 1′ via a bonding wire. External contact G2His connected to a gate terminal of fourth power transistor 5HB of thehigh side of semiconductor power module 1 via a bonding wire.

SUMMARY

A semiconductor power module in accordance with an example embodiment ofthe present invention may have the advantage that the effectiveinductances and ohmic resistances of the two power transistors situatedin parallel between a first collector strip conductor and a firstemitter strip conductor are adapted to one another via a particular linerouting. This results in symmetrical control voltages at the twoparallel power transistors, and in uniform switching on and switchingoff, so that the energy input is equally distributed over the twoparallel power transistors during normal operation and in the event of ashort circuit. An ideal chip surface area for both power transistors maythus be determined during normal operation. In the event of a shortcircuit, the equal distribution of the currents results in maximumutilization of the thermal destruction limit of the two powertransistors. In addition, due to the electrical symmetry with equaleffective control voltages at the two power transistors, the distancebetween the two parallel power transistors may be increased, thusenabling a better cooling connection.

Specific example embodiments of the present invention provide asemiconductor power module that includes a first power transistor and asecond power transistor that are situated in parallel between a firstcollector strip conductor and a first emitter strip conductor, in eachcase a first connection surface of the power transistors beingelectroconductively connected to the first collector strip conductor,and in each case a second connection surface of the power transistorsbeing electroconductively connected to the first emitter stripconductor, so that a current flowing between the first collector stripconductor and the first emitter strip conductor is divided between thetwo power transistors when the power transistors are each conductivelyconnected via an applied control voltage. A first external power contactis directly contacted with the first collector strip conductor at afirst contact area. A second external power contact is contacted withthe first emitter strip conductor at a second contact area via a firstconnecting element, the second contact area being positionedmechanically asymmetrically between the power transistors connected tothe first emitter strip conductor in such a way that an electricalsymmetry with identical effective control voltages results at the twopower transistors.

Advantageous improvements of the semiconductor power module inaccordance with the present invention are possible due to measures andrefinements set forth herein.

It is particularly advantageous if a third power transistor and a fourthpower transistor may be situated in parallel between a second collectorstrip conductor and a second emitter strip conductor, it being possiblein each case for a first connection surface of the power transistors tobe electroconductively connected to the second collector stripconductor, and it being possible in each case for a second connectionsurface of the power transistors to be electroconductively connected tothe second emitter strip conductor, so that a current flowing betweenthe second collector strip conductor and the second emitter stripconductor may be divided between the two power transistors when thepower transistors are each conductively connected via an applied controlvoltage. A third external power contact may be directly contacted withthe second collector strip conductor at a third contact area, and thesecond emitter strip conductor may be contacted with the first collectorstrip conductor at a fourth contact area via a second connectingelement. In addition, the first power transistor and the second powertransistor connected in parallel may form a low-side path between thesecond external power contact and the first external power contact, andthe third power transistor and the fourth power transistor connected inparallel may form a high-side path between the third external powercontact and the first external power contact. In addition, a firstfree-wheeling diode may be situated in parallel with the first powertransistor and with the second power transistor, between the firstcollector strip conductor and the first emitter strip conductor. Asecond free-wheeling diode may be situated in parallel with the thirdpower transistor and with the fourth power transistor, between thesecond collector strip conductor and the second emitter strip conductor.The semiconductor power module may thus be used as a B2 bridge, analternating voltage potential then being present at the first externalpower contact, a first direct voltage potential being present at thesecond external power contact, and a second direct voltage potentialbeing present at the third external power contact. The power transistorsmay be designed, for example, as insulated gate bipolar transistors(IGBTs), metal oxide semiconductor field effect transistors (MOSFETs),etc.

In a further advantageous embodiment of the semiconductor power modulein accordance with the present invention, the fourth contact area may bepositioned mechanically and electrically symmetrically between the twopower transistors, based on the distance between the third powertransistor and the fourth power transistor connected in parallel. Thisresults in symmetrical control voltages at the two parallel powertransistors, and in uniform switching on and switching off, so that theenergy input is equally distributed over the two parallel powertransistors during normal operation and in the event of a short circuit.

In a further advantageous embodiment of the semiconductor power modulein accordance with the present invention, the second contact area may bemechanically shifted in the direction of the second power transistor,which is spatially farther from the second power contact than is thefirst power transistor, based on the distance between the first powertransistor and the second power transistor. As a result, the effectiveinductance and the effective ohmic resistance of the first powertransistor are increased and the effective inductance and the effectiveohmic resistance of the second power transistor are reduced, as theresult of which the effective inductances and ohmic resistances of thetwo power transistors are adapted to one another.

In a further advantageous embodiment of the semiconductor power modulein accordance with the present invention, a first control voltage may beapplied between an external emitter contact and a first external gatecontact that is connected to a control connection of the first powertransistor. Furthermore, a second control voltage may be applied betweenthe external emitter contact and a second external gate contact that isconnected to a control connection of the second power transistor. Inaddition, the external emitter contact may be connected to the firstemitter strip conductor at an emitter contacting point. The emittercontacting point with the first emitter strip conductor may bemechanically shifted in the direction of the first power transistor,based on the distance between the first power transistor and the secondpower transistor.

In a further advantageous embodiment of the semiconductor power modulein accordance with the present invention, the first connecting elementmay have a U-shaped design, so that an air gap is formed between thesecond connecting element and the second emitter strip conductor, exceptat the second contact area. This allows a particularly simple andcost-effective implementation of the positioning of the second contactarea. In addition, the U-shaped design of the first connecting elementallows a simple implementation of a heat dissipation path fordissipating heat from the second external power contact.

In a further advantageous embodiment of the semiconductor power modulein accordance with the present invention, a heat dissipation system thatincludes an electrically insulating intermediate layer that isintegrally joined to the first connecting element via a first solderlayer and integrally joined to the first collector strip conductor via asecond solder layer may be situated in the area of the second externalpower contact, it being possible for the electrically insulatingintermediate layer to form an electrically insulated heat dissipationpath between the first connecting element and the first collector stripconductor, which dissipates the heat of the second external powercontact. Due to the electrically insulated heat dissipation path, it ispossible to thermally couple the second external power contact of thesemiconductor module, which is not directly contacted on the surface ofa collector strip conductor which acts as a heat sink, to the firstcollector strip conductor which acts as a heat sink, and dissipate theheat therefrom. As a result, such external power contacts of thesemiconductor power module may also be cooled, and the power loss may bedischarged via the heat dissipation path of the semiconductor powermodule. Due to the heat dissipation system, the second external powercontact is thermally coupled to the cooling system of the semiconductorpower module, so that a defined dissipation of heat of the externalpower contact is possible. In addition, the thermal performance of thesemiconductor power module is advantageously decoupled from power lossthat is applied from the outside. Furthermore, the power transistorsexperience no additional heat input due to the connection to externalbusbars, and may thus be utilized in a more optimal manner.

One exemplary embodiment of the present invention is illustrated in thefigures and explained in greater detail in the following description. Inaddition, a conventional semiconductor power module from the related artand described in the introduction is illustrated in the figures.Identical reference symbols in the drawings denote components orelements having the same or analogous functions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic illustration of one exemplary embodiment of asemiconductor power module according to the present invention.

FIG. 2 shows a schematic illustration of a conventional semiconductorpower module from the related art.

FIG. 3 shows a schematic electrical circuit diagram of the semiconductorpower module according to the present invention from FIG. 1.

FIG. 4 shows a characteristic curve diagram of the switching behavior ofthe conventional semiconductor power module from FIG. 2.

FIG. 5 shows a characteristic curve diagram of the switching behavior ofthe semiconductor power module according to the present invention fromFIGS. 1 and 3.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

As is apparent from FIGS. 1 and 3, the illustrated exemplary embodimentof a semiconductor power module 1 according to the present inventionincludes a first power transistor 5LA and a second power transistor 5LBthat are situated in parallel between a first collector strip conductor11L and a first emitter strip conductor 9L, in each case a firstconnection surface of power transistors 5LA, 5LB beingelectroconductively connected to first collector strip conductor 11L,and in each case a second connection surface of power transistors 5LA,5LB being electroconductively connected to first emitter strip conductor9L, so that a current flowing between first collector strip conductor11L and first emitter strip conductor 9L is divided between the twopower transistors 5LA, 5LB when power transistors 5LA, 5LB are eachconductively connected via an applied control voltage. A first externalpower contact P is directly contacted with first collector stripconductor 11 at a first contact area KB1. A second external powercontact TL is contacted with first emitter strip conductor 9L at asecond contact area KB2 via a first connecting element 13, secondcontact area KB2 being positioned mechanically asymmetrically betweenpower transistors 5LA, 5LB connected to first emitter strip conductor 9Lin such a way that an electrical symmetry with identical effectivecontrol voltages results at the two power transistors 5LA, 5LB.

As is further shown in FIGS. 1 and 3, illustrated semiconductor powermodule 1 includes a third power transistor 5HA and a fourth powertransistor 5HB that are situated in parallel between a second collectorstrip conductor 11H and a second emitter strip conductor 9H, in eachcase a first connection surface of power transistors 5HA, 5HB beingelectroconductively connected to second collector strip conductor 11H,and in each case a second connection surface of power transistors 5HA,5HB being electroconductively connected to second emitter stripconductor 9H, so that a current flowing between second collector stripconductor 11H and second emitter strip conductor 9H is divided betweenthe two power transistors 5HA, 5HB when power transistors 5HA, 5HB areeach conductively connected via an applied control voltage. In addition,a third external power contact TH is directly contacted with secondcollector strip conductor 11H at a third contact area KB3. Secondemitter strip conductor 9H is contacted with first collector stripconductor 11L at a fourth contact area KB4 via a second connectingelement 12. As is further apparent from FIG. 1, fourth contact area KB4is positioned mechanically and electrically symmetrically between thetwo power transistors 5HA, 5HB, based on the distance between thirdpower transistor 5HA and fourth power transistor 5HB connected inparallel.

As is further shown in FIGS. 1 and 3, semiconductor power module 1 inthe illustrated exemplary embodiment is designed as a B2 bridge 1A.Therefore, an alternating voltage potential is present at first externalpower contact P. A first direct voltage potential is present at secondexternal power contact TL, and a second direct voltage potential ispresent at third external power contact TH. Analogously to conventionalsemiconductor power module 1′ from the related art illustrated in FIG.2, power transistors 5LA, 5LB, 5HA, 5HB are each designed as insulatedgate bipolar transistors (IGBTs). In the illustrated exemplaryembodiment of semiconductor power module 1, first power transistor 5LAand second power transistor 5LB connected in parallel form a low-sidepath between second external power contact TL and first external powercontact P. Third power transistor 5HA and fourth power transistor 5HBconnected in parallel form a high-side path between third external powercontact TH and first external power contact P. In addition, a firstfree-wheeling diode 3L is situated in the low-side path in parallel tofirst power transistor 5LA and to second power transistor 5LB, betweenfirst collector strip conductor 11L and first emitter strip conductor9L. A second free-wheeling diode 3H is situated in the high-side path inparallel to third power transistor 5HA and to fourth power transistor5HB, between second collector strip conductor 11H and second emitterstrip conductor 9H. The two collector strip conductors 11L, 11H arespaced apart from one another in the same plane and are coupled to acooling device, not illustrated. Therefore, the two collector stripconductors 11L, 11H each act as a heat sink for dissipating heat fromsemiconductor power module 1. In addition, the heat of power transistors5LA, 5LB, 5HA, 5HB and of free-wheeling diodes 3L, 3H is dissipated viarespective collector strip conductor 11L, 11H.

First external power contact P is directly connected to the surface offirst collector strip conductor 11L at first contact area KB1 andundergoes heat dissipation via same. In the illustrated exemplaryembodiment, second external power contact TL is connected to firstemitter strip conductor 9L at a second contact area KB2 via firstconnecting element 14. In the illustrated exemplary embodiment, firstconnecting element 13 has a U-shaped design, so that an air gap 15 isformed between second connecting element 13 and second emitter stripconductor 9B, except at second contact area KB2. Furthermore, in theillustrated exemplary embodiment a heat dissipation system 20 thatincludes an electrically insulating intermediate layer, not illustrated,that is integrally joined to first connecting element 13 via a firstsolder layer and integrally joined to first collector strip conductor11L via a second solder layer is situated in the area of second externalpower contact TL. The electrically insulating intermediate layer formsan electrically insulated heat dissipation path between first connectingelement 13 and first collector strip conductor 11L, which dissipates theheat of second external power contact TL. The electrically insulatingintermediate layer, not illustrated, is designed as an AMB ceramicsubstrate, for example, and has good to very good heat conductivity in arange of 20 to 200 W/mK. The AMB ceramic substrate has a copperstructure as a solderable surface at both surfaces, so that theintegrally joined solder layers in question may be created for heatdissipation between first connecting element 13 and the electricallyinsulating intermediate layer, and between the electrically insulatingintermediate layer and first collector strip conductor 11L. Of course,the electrically insulating intermediate layer may alternatively bedesigned as a DBC substrate or as an IMS substrate or as a piece ofultra-pure silicon. Third external power contact TH is directlyconnected to the surface of second collector strip conductor 11H atthird contact area KB3 and undergoes heat dissipation via same. Inaddition, illustrated semiconductor power module 1 includes even furtherexternal contacts KH, EH, G1H, G2H, KL, EL, G1L, G2L. External contactKL is connected to first collector strip conductor 11L or the collectorterminals of power transistors 5LA, 5LB of the low side of semiconductorpower module 1 via a bonding wire. External contact EL is connected tofirst emitter strip conductor 9L or emitter terminals of powertransistors 5LA, 5LB of the low side of semiconductor power module 1 viaa bonding wire. External contact G1L is connected to a gate terminal offirst power transistor 5LA of the low side of semiconductor power module1 via a bonding wire. External contact G2L is connected to a gateterminal of second power transistor 5LB of the low side of semiconductorpower module 1 via a bonding wire. Analogously, external contact KH isconnected to second collector strip conductor 11H or collector terminalsof power transistors 5HA, 5HB of the high side of semiconductor powermodule 1 via a bonding wire. External contact EH is connected to secondemitter strip conductor 9H or emitter terminals of power transistors5HA, 5HB of the high side of semiconductor power module 1 via a bondingwire. External contact G1H is connected to a gate terminal of thirdpower transistor 5HA of the high side of semiconductor power module 1via a bonding wire. External contact G2H is connected to a gate terminalof fourth power transistor 5HB of the high side of semiconductor powermodule 1 via a bonding wire.

As is further shown in FIG. 1, second contact area KB2 is mechanicallyshifted in the direction of second power transistor 5LB, which isspatially farther from second power contact TL than is first powertransistor 5LA, based on the distance between first power transistor 5LAand second power transistor 5LB. In addition, a first control voltage isapplied between external emitter contact EL and first external gatecontact G1L that is connected to the control connection of first powertransistor 5LA. A second control voltage is applied between externalemitter contact EL and second external gate contact G2L that isconnected to the control connection of second power transistor 5LB.External emitter contact EL is connected to first emitter stripconductor 9LB at an emitter contacting point EK. Emitter contactingpoint EK with first emitter strip conductor 9LB is mechanically shiftedin the direction of first power transistor 5LA, based on the distancebetween first power transistor 5LA and second power transistor 5LB.

In FIG. 3, reference symbol R in each case denotes a corresponding lineresistance, and reference symbol L denotes a corresponding lineinductance. The factors denoted by reference symbol x may be set by thepositioning of second contact area KB2 and/or of emitter contactingpoint EK in order to adapt the ohmic line resistances and the lineinductances to the emitter of power transistors 5LA, 5LB or to the anodeof free-wheeling diode 3L.

As is apparent from a comparison of the two characteristic curvediagrams in FIGS. 4 and 5, by use of specific embodiments ofsemiconductor power module 1 according to the present invention thecurrent distribution over the two power transistors 5LA, 5LB may be setin such a way that a current difference DI, illustrated in FIG. 5,between a current flow I-5LA through first power transistor 5LA and acurrent flow I-5LB through second power transistor 5LB is much lowercompared to current difference DI′, illustrated in FIG. 4, for samevoltage pattern UCE-5L.

1-12. (canceled)
 13. A semiconductor power module, comprising: a firstpower transistor and a second power transistor that are situated inparallel between a first collector strip conductor and a first emitterstrip conductor, a first connection surface of each of the first andsecond power transistors being electroconductively connected to thefirst collector strip conductor, a second connection surface of each ofthe first and second power transistors being electroconductivelyconnected to the first emitter strip conductor, so that a currentflowing between the first collector strip conductor and the firstemitter strip conductor is divided between the first and second powertransistors when the first and second power transistors are eachconductively connected via an applied control voltage, a first externalpower contact being directly contacted with the first collector stripconductor at a first contact area, a second external power contact beingcontacted with the first emitter strip conductor at a second contactarea via a first connecting element, and the second contact area beingpositioned mechanically asymmetrically between the first and secondpower transistors connected to the first emitter strip conductor in sucha way that an electrical symmetry with identical effective controlvoltages results at the first and second power transistors.
 14. Thesemiconductor power module as recited in claim 13, wherein a third powertransistor and a fourth power transistor are situated in parallelbetween a second collector strip conductor and a second emitter stripconductor, a first connection surface of each of the third and fourthpower transistors being electroconductively connected to the secondcollector strip conductor, and a second connection surface of each ofthe third and fourth power transistors being electroconductivelyconnected to the second emitter strip conductor, so that a currentflowing between the second collector strip conductor and the secondemitter strip conductor is divided between the third and fourth powertransistors when the third and fourth power transistors are eachconductively connected via an applied control voltage, a third externalpower contact being directly contacted with the second collector stripconductor at a third contact area, and the second emitter stripconductor being contacted with the first collector strip conductor at afourth contact area via a second connecting element.
 15. Thesemiconductor power module as recited in claim 15, wherein the firstpower transistor and the second power transistor connected in parallelform a low-side path between the second external power contact and thefirst external power contact, and the third power transistor and thefourth power transistor connected in parallel form a high-side pathbetween the third external power contact and the first external powercontact.
 16. The semiconductor power module as recited in claim 15,wherein a first free-wheeling diode is situated in parallel to the firstpower transistor and to the second power transistor, between the firstcollector strip conductor and the first emitter strip conductor, and asecond free-wheeling diode is situated in parallel to the third powertransistor and to the fourth power transistor, between the secondcollector strip conductor and the second emitter strip conductor. 17.The semiconductor power module as recited in claim 14, wherein thefourth contact area is positioned mechanically and electricallysymmetrically between the third and fourth power transistors, based on adistance between the third power transistor and the fourth powertransistor connected in parallel.
 18. The semiconductor power module asrecited in claim 13, wherein the second contact area is mechanicallyshifted in a direction of the second power transistor, which isspatially farther from the second power contact than is the first powertransistor, based on the distance between the first power transistor andthe second power transistor.
 19. The semiconductor power module asrecited in claim 18, wherein a first control voltage is applied betweenan external emitter contact and a first external gate contact that isconnected to a control connection of the first power transistor.
 20. Thesemiconductor power module as recited in claim 19, wherein a secondcontrol voltage is applied between the external emitter contact and asecond external gate contact that is connected to a control connectionof the second power transistor.
 21. The semiconductor power module asrecited in claim 19, wherein the external emitter contact is connectedto the first emitter strip conductor at an emitter contacting point. 22.The semiconductor power module as recited in claim 21, wherein theemitter contacting point with the first emitter strip conductor ismechanically shifted in a direction of the first power transistor, basedon a distance between the first power transistor and the second powertransistor.
 23. The semiconductor power module as recited in claim 13,wherein the first connecting element has a U-shaped design, so that anair gap is formed between the second connecting element and the secondemitter strip conductor, except at the second contact area.
 24. Thesemiconductor power module as recited in claim 13, wherein a heatdissipation system that includes an electrically insulating intermediatelayer is situated in an area of the second external power contact, theelectrically insulating intermediate layer being integrally joined tothe first connecting element via a first solder layer and integrallyjoined to the first collector strip conductor via a second solder layer,the electrically insulating intermediate layer forming an electricallyinsulated heat dissipation path between the first connecting element andthe first collector strip conductor, which dissipates heat of the secondexternal power contact.